Drill jig



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W. BETZ DRILL JIG Feib, 4-, 1936..

5 sheets-sheet 1 Filed Jan. 14, 1933 r M n e m 1 fl Home y W, BETZ DRILLJIG Feb 4, W36

Filed Jan. 14,' 1955 3 Sheets-Sheet 2 William Be 2 llorney Feb. 4, 193.w. BETZ DRILL JIG Filed Jan. 14, 1933 3 Sheets-Sheet 5 Inventor PatentedFeb. 4, 1936 UNITED STATES PATENT OFFICE DRILL JIG William Betz,Detroit, Mich. Application January 14, 1933, Serial No. 651,800

3 Claims.

The present invention relates to new and useful improvements in drilljigs, and has for its primary object to provide, in a manner ashereinafter set forth, a jig of this character embodying a novelconstruction, combination and arrangement of parts through the medium ofwhich a center hole and a plurality of holes equally or unequallyeccentric with respect to the center hole may be expeditiously drilledin the work.

Other objects of the invention are to provide a drill jig of theaforementioned character which will be simple in construction, strong,durable, light in weight, compact accurate, and which may bemanufactured at low cost.

All of the foregoing and still further objects and advantages of theinvention will become apparent from a study of the followingspecification, taken in connection with the accompanying drawingswherein like characters of reference designate corresponding partsthroughout the several views, and wherein:-

Figure 1 is a view in top plan of a drill jig constructed in accordancewith the present invention.

Fig. 2 is a view in side elevation thereof.

Fig. 3 is a view in vertical transverse section,

taken approximately on the line 3-3 of Fig. 2.

Fig. 4 is a view in vertical transverse section,

taken approximately on the line 4-4 of Fig. 1.

Fig. 5 is a detail view in perspective of the base of the jig.

Fig. 6 is a detail view in perspective of one of the removable bushings.

Fig. '7 is a detail view in perspective of one of 35 the slidable bushblocks.

Fig. 8 is a view in vertical longitudinal section, showing the manner ofmarking the work for the outer drills.

Fig. 9 is a view in vertical longitudinal section,

4 showing one of the outer drills in operative position in one of thebush blocks.

Fig. 10 is a plan 'view of a piece of completed work.

' Fig. ll is a detail view in perspective of one of 45 the centerpunches.

Referring now to the drawings in detail, it will be seen that thereference numeral I designates an elongated metal base having a pair oflongitudinally spaced and aligned longitudinal slots or openings 2therein. A center hole 3 extends vertically through the bar I betweenthe slots or openings 2, the purpose of which hole 3 will be presentlyset forth. Extending longitudinally in 55 the longitudinal side edges ofthe base I are grooves 4, the purpose of which also will be presentlyset forth.

Mounted for longitudinal sliding movement on the base I in each of theslots 2 is a generally rectangular bush block 5. As the bush blocks 5 5are of identical construction, a detailed description of one willsuffice for both. Each of the bush blocks 5 has formed in its bottom atrans-- versely spaced pair of vertical channels 6 for slidablyreceiving the side portions of the base I 1 for slidably mounting thebush blocks on the base for longitudinal adjustment. Each block 5 iscentrally provided with a vertical hole I. A transverse channel 8 in thetop of the block, communicates with the upper end of the hole. Set 15screws 9 are threaded horizontally through openings Ill provided in thelower part of opposite sides of the blocks 5, said set screws beingarranged to be engaged in the grooves i of the base for locking theblocks in adjusted positions on the 20 bar l in a manner to precludemovement of the bush blocks in any direction while so locked.

The vertical holes I of the blocks 5 are for the reception of removablebushings ll having elongated, substantially flat supporting heads it on25 their upper ends which rest or seat in the transverse channels 8 ofsaid blocks so as to prevent the bushings from turning while a drill isbeing operated therein. The bushings II are counterbored at their upperends, as indicated at I3. 30 The ends of the heads I2 of the bushingsare curved and have formed in the upper surface thereof half-moon shapedrabbets or notches I4 for the reception of the lateral lug of bushinglocking screws l5 which are threaded into the vertical sockets It whichare provided therefor in the side portions of the blocks 5.

In Figure 11 is shown a center punch I! which is to be placed in theopening 3 of the base or in either of the openings 1 of the bush blocks5 (the bushings having been removed) for marking the work in an obviousmanner. The reference numeral I8 designates a plug which is to be placedin the center hole 3 of the base while the work is being marked for theouter holes and while such outer holes are being drilled, the plug I8being arranged to extend below the base when engaged in the opening 3 ofthe base I and be engaged in the center hole which is first drilled inthe work. The plug I8 constitutes an axle about which the base I is toberotatably adjusted for giving the bar different angular positions formarking or drilling the outer holes. In Figs. 8 to 10, inclusive, of thedrawing, the work is designated by the reference numeral I9.

Briefly, follows:-

The center of the work is first located and a comparatively shallowsocket or hole is then drilled therein. The base I is then positioned onthe work with the center hole 3 over the comparatively shallow socketand the punch I! is then placed in the center hole with its pointed endlowermost. As the lower end of the punch becomes seated in the saidsocket, the jig is retained in the desired position on the work, and isthen to be clamped by suitable means (not shown). If a center hole isdesired in the work, the punch I! may then be removed and a bushingsubstituted therefor in the center hole 3, a drill of the desired sizebeing then inserted in the bushing and the drilling operation performed.After the drill has been withdrawn at the completion of the drillingoperation and the bushing removed, a plug l8 may be inserted in thebushing in the center hole 3 to extend into the center hole in the workresulting from the drilling operation and hold the jig againsttranslatory movement and to constitute a center pivot about which torotate the base, as shown in Figures 8 and 9.

Upon completion of the described operations, the blocks 5 are thenadjusted to the desired position on the base I, the exact distance fromthe center of the base being ascertained by measuring with a micrometerthe distance between the plug I8 and a center punch I! inserted in theblock, allowance being made for the diameter of the plug [8 and for thediameter of the punch l1. After the bush blocks have been adjusted tothe desired positions and locked in place by the set screws 9, thecenter punches I! are removed, replaced by bushings I I, and the drillsinserted in the bushings. In Figure 9 of the drawings, a portion of adrill bit is indicated at 20. It will thus be seen that a diametricallyaligned series of three holes may be drilled without moving the jig.

It is obvious that one of the center punches I! or plugs l8 may beutilized in one bush block while engaged with the work, while theremaining bush block is occupied in a drilling operation, to preventrotation of the base out of its appointed position. Any proper methodfor gauging the rotation of the jig to the next angular position maybeutilized after the first series of holes has been made.

It is believed that the many advantages of a drill jig constructed inaccordance with the present invention will be readily understood,particularly by those skilled in the art, and although the preferredembodiment of the invention is as illustrated and described herein, itis to be understood that changes in the details of construction and inthe combination and arrangement of parts may be resorted to which willfall within the scope of the invention as claimed.

Having thus described my invention, what I claim as new is:

1. A drill jig comprising a base for resting on the work and providedwith an elongated opening defining a pair of spaced parallel bars, theouter sides of said bars being formed with a the manner of using the jigis as groove, a block provided in its bottom with a. pair of spacedlongitudinal grooves arranged to receive the respective bars so that thebottoms of the grooves slide on the tops of said bars and the oppositesides of the grooves slidably engage the opposite sides of the bars, setscrews traversing the outer sides of said block and engaging in therespective grooves in the outer sides of the bars so as to lock theblock in adjustable positions on said base, said block being formed inits top with a transverse groove into which the said bottoms of thegrooves open, said block being further formed with a. vertical boreplaced between said grooves and between the sides of said transversegroove, a drill bushing having a tubular shank fitting in said bore anda lateral shoulder on its upper end conformably seating in saidtransverse groove and resting on the tops of said bars appearing in theopen portion of said bottoms, and screw clamp means threaded into thefloor of said transverse groove outwardly of said open portions of thebottoms, said clamp means having a lateral arm arranged to swing overand forcibly engage the top of the bushing as the screw means is turnedin a direction to thread the same into said floor.

2. A drill jig comprising a base for resting on the work and formed witha longitudinal groove in one side, a bush block provided in its bottomwith a slot arranged to receive said base and rest slidably on the upperpart of said base, a set screw traversing one side of said block andengaging said longitudinal groove, said block being formed with avertical bore arranged to receive a drill bushing, vided with a widetransverse groove into which said slot opens, a bushing seated in saidvertical bore and having a flange fitting into said transverse grooveand resting on the top of said base,

and a screw threaded vertically in the top of 4 said block and having alateral arm arranged to swing over and forcibly engage the top of saidflange as the screw is turned down, said arm and said set screw thencooperating to clamp said bushing, said block, and said base together.

3. A device of the character described, said device comprising a basefor resting on the work, said base having a longitudinal groove formedalong one vertical side thereof, a slide mounted the top of said bushblock being proon said base and formed with a longitudinal slot in itsbottom receiving said base and a transverse slot in its top, said slotsopening into each other so as to expose the top of said base within saidtransverse slot, a set screw traversing one side of said slide andengaging in said longitudinal groove of the base, said slide beingformed with a vertical bore opening into said transverse groove, abushing seated in said bore and having a flange fitting in saidtransverse groove and resting on the floor thereof, a clamp screw Mthreaded into the top of said slide and having a lateral arm arranged toswing onto and forcibly engage the top of said flange when said clampscrew is turned so as to thread the same into said slide whereby saidclamp screw and said set screw \I cooperate in frictionally locking saidbase, said slide, and said bushing together.

WILLIAM BETZ.

